Issue 66

S.E. Daguiani et alii, Frattura ed Integrità Strutturale, 66 (2023) 88-111; DOI: 10.3221/IGF-ESIS.66.05

C ONCLUSION

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n this study, an experimental investigation was conducted to study the influence of waste glass powder (WGP) and ground granulated blast furnace slag (GGBS) as supplementary cementitious materials (SCMs). Analyses of fresh, mechanical, and microstructural properties were performed. The following conclusions can be drawn from the results obtained:  The mixture design approach allowed for precise mathematical models and prediction values of consistency, setting time, strength, and resistance activity index of the examined pastes and mortars.  Incorporating 7.5% WGP and 7.5% GGBS in the cement reduced water requirements by 0.5% and 0.6% to achieve a normal paste consistency. Furthermore, the addition of 22.5% GGBS in ternary binders resulted in an additional improvement of approximately 3.4% in consistency.  WGP and GGBS-based mixes exhibited longer initial and final setting times in accordance with ASTM C150 standards.  Partial cement replacement with WGP up to 20% led to a 21% decrease in the strength activity index at 28 days compared to the reference mortar. Similarly, replacing 20% of the binder with GGBS achieved a maximum strength of 47.5 MPa, corresponding to a 2% reduction in the strength activity index.  Incorporating 5% WGP and 5% GGBS in ternary binders significantly reduced the total porosity of the samples, promoting a compressive strength of 48.5 MPa at 28 days, compared to the 48.47 MPa of the control mix.  The results of the strength activity index exceeded 75% at 7 and 28 days, indicating positive pozzolanic activity of WGP and GGBS when replacing cement.  X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) analyses revealed that the hydration process resulted in the formation of additional calcium silicate hydrate (C-S-H) gel, contributing to the strength and durability of the paste. This study provides valuable insights into the potential use of recycled materials in construction and can contribute to promoting the transition towards a more sustainable and environmentally friendly building industry.

N OMENCLATURE

PC: Portland Cement SCMs: Supplementary Cementitious materials GGBS: Ground Granulated Blast Furnace Slag WGP: Waste Glass Powder (W/C): (Water / Cement) ratio 7-days SAI: Strength-Activity Index at 7 days 28-days SAI: Strength-Activity Index at 28 days

A CKNOWLEDGEMENTS

T

he authors would like to acknowledge the directorate general for scientific research and technological development “DGRSDT” -Algeria- for financial support, and the performance directorate of the Biskria cement company where this work was conducted for their technical support.

R EFERENCES

[1] Laoufi, L., Senhadji, Y., Benazzouk, A. (2016). Valorization of mud from Fergoug dam in manufacturing mortars, Case Stud. Constr. Mater., 5, pp. 26–38, DOI: 10.1016/j.cscm.2016.06.002. [2] Al-Mansour, A., Chow, C.L., Feo, L., Penna, R., Lau, D. (2019). Green concrete: By-products utilization and advanced approaches, Sustain., 11(19), pp. 1–30, DOI: 10.3390/su11195145.

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